1. Field of the Invention
The invention relates to a method of cooling electronic circuit boards using surface mounted devices. Further, the invention relates to a heat sink device for cooling electronic circuit boards using surface mounted devices.
2. Description of Related Art
In most electronic circuit boards, temperature results from the electronic function of the board, or rather the electronically active parts on the board. Increased temperatures are in fact a main reason for defects of electronic devices.
Temperature-critical applications use lumped heat sinks to reduce the temperature of the electronic components. However, the space available on or around the components is limited in many cases.
A known method of cooling electronic circuit boards, which surface mounted devices are placed on, uses a fan to increase the airflow. Unfortunately, the increased airflow results in higher acoustic noise level and in increased energy costs. Another known method uses a heat sink or cooling unit placed on a surface mounted device, which produces heat (e.g. microprocessors) under operating conditions. This solution requires an additional mechanical production step with additional costs.
Another solution is to use a thermally conductive interface material between the thermal hot spot and a heat sink. This heat sink can be a lumped heat sink or the chassis of the equipment. A cooling area on the printed circuit board can be used as a heat sink, too. These solutions, however, require an additional mechanical production step with additional costs. The cooling results depend on the skills of the employee in the production flow.
If there are large unused areas on the printed circuit board, lumped heat sinks are the state of the art to cool the boards. Unfortunately, in many cases, this results in a certain distance between the hot spot and such lumped heat sink, which decreases the effect of dissipating heat from the board. Moreover, in many cases, the space available is limited and the use of a lumped heat sink is not possible.
However, in the layout of some boards, there is not even enough room or space on the board to place further fans or cooling units. Another known method is to use a copper or aluminum core inside the board. This solution is intended to spread the heat and to use a larger board area for cooling. Unfortunately, this solution is quite expensive and is not available from every board manufacturer.
It is therefore an object of the present invention to provide a method of cooling electronic circuit boards, on which surface mounted devices are placed or have to be placed. It is a further object of the invention to provide a heat sink device adapted to realize the method according to the invention.